Impact of immune checkpoint inhibitor (ICI)-associated autoimmune hemolytic anemia (AIHA) on mortality in cancer patients: A retrospective analysis.

2649 Background: Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment but can cause serious immune-related adverse events; including rare yet severe autoimmune hemolytic anemia (AIHA) . This study evaluates the impact of ICI-associated AIHA on mortality in patients with solid cancers. Methods: A retrospective analysis using the TriNetX database examined patients with solid cancers treated with ICIs. Patients were defined using ICD-10 codes and grouped into those who developed AIHA after ICI use and those who did not. Baseline characteristics, including cancer diagnosis, ICI medications, and comorbidities, were compared between groups using TriNetX's built-in t-tests and z-tests to calculate p-values. Confounding variables were adjusted with 1:1 propensity score matching. Primary outcomes were 30- and 60-day mortality; secondary outcomes included transfusions and hospitalizations. Outcomes were evaluated using measures of association, Kaplan-Meier log-rank tests, and a Cox proportional hazards model. Results: Among 106,388 ICI-treated patients, 352 developed AIHA. After matching (352 per group), the AIHA group had a significantly higher 30-day mortality (15.25% vs. 5.14%; OR 3.493, 95% CI: 1.898-5.803, p < 0.0001) and 60-day mortality (22.87% vs. 6.86%; OR 4.195, 95% CI: 2.479-6.54, p < 0.001). Transfusions (OR 4.085, 95% CI: 2.897-6.525, p < 0.0001) and hospitalizations (OR 1.865, 95% CI: 1.525-2.837, p < 0.0001) were also significantly higher in the AIHA group. Hazard ratios (HR) confirmed significant mortality risks in AIHA group at 30 days (HR: 3.16, 95% CI: 1.849-5.402, p < 0.0001) and 60 days (HR: 3.673, 95% CI: 2.324-5.805, p < 0.0001) (table 1). HRs for transfusion and hospitalization were 4.309 (95% CI: 2.975-6.241, p < 0.0001) and 2.049 (95% CI: 1.692-2.48, p < 0.0001), respectively. Conclusions: This study highlights the clinical impact of ICI-associated AIHA, which is linked to higher mortality at 30 and 60 days, as well as increased transfusion and hospitalization rates. Although rare, ICI-associated AIHA is a potentially fatal complication. Clinicians should maintain a high level of suspicion for AIHA in patients on ICIs, as early recognition and intervention may improve outcomes. Primary Outcomes HR 95 % Confidence Interval P-Value Mortality within 30-days* 3.16 (1.849,5.402) < 0.0001 Mortality within 60-days* 3.673 (2.324,5.805) < 0.0001 Transfusion 4.309 (2.975,6.241) < 0.0001 Hospitalization oremergency services 2.049 (1.692,2.48) < 0.0001